US 4,797,962 A · Closed loop feedback air supply for air support beds

Abstract

A closed loop feedback-controlled air supply system for air support convalescent beds having groups of air sacs for supporting various body sections of a patient. The air supply system may be self-contained with its own air supply compressor or it may utilize any other source of compressed air. The air supply is coupled with a distributor manifold from which extends a plurality of air supply lines extending to selected groups of air sacs. Servo valves controlling each of the air supply lines are automatically positioned and controlled by signals from a microprocessor, the microprocessor receiving pressure feedback monitoring signals from pressure transducers associated with each of the groups of air sacs. Between the air supply and the manifold may be provided a master control valve which may be a servo valve also activated and controlled by the microprocessor responsive to feedback signals. Where the air supply is provided by a variable speed compressor, the compressor may also be responsive to control signals from the microprocessor.

Claims13

Dependent claims

In a low air loss air support convalescent bed having a plurality of low air loss air sacs that are maintained within a desired pressure range and are arranged for supporting various body sections of a patient, the improvement comprising:

(a) air supply means for supplying compressed air at a pressure in excess of said desired pressure range of any of said air sacs;
(b) air distributing means for distributing compressed air from said air supply means to said plurality of air sacs;
(c) pressure control means having a plurality of servo valves for conducting air at preset pressure ranges to individual air sacs;
(d) pressure monitoring means continuously monitoring the air pressure of each of said air sacs and providing pressure indicative signals;
and
(f) feedback means receiving said pressure indicative signals and providing pressure signals to said pressure control means for each of said air sacs, said pressure control means adjusting said servo valves appropriately to maintain the proper pressure range in each of said air sacs, whereby the selected interface pressure between the air sacs and the patient is established.

3 more elements

A method of maintaining and adjusting inflation of the air sacs of a low air loss air support bed having multiple air sacs forming a plurality of air sac groups, comprising:

(a) supplying air from a source of compressed air having air pressure exceeding the maximum expected air pressure desired for any of said air sacs and at a volume exceeding the cumulative air loss from said air sacs;
(b) distributing compressed air to a plurality of air supply ducts, there being an air supply duct for said air sacs;
(c) by control means controlling the pressure and volume of air flowing through each of said air supply ducts to the respective air sacs in communication therewith;
(d) sensing the air pressure in said air sacs and providing pressure indicating signals for said air sacs representing said air pressure therein;
and
(e) receiving and electronically processing said pressure indicating signals and transmitting control signals to said control means responsive to said pressure indicating signals for automatic adjustment of the respective air pressures of said air sacs, whereby the selected interface pressure between the air sacs and the patient is established.

3 more elements

Dependencies are inferred from the claim text.

Closed loop feedback air supply for air support beds

Life of this patent

Closed loop feedback air supply for air support beds

Life of this patent

Abstract

Claims13